6 POPULAR SCIENCE MONTHLY 



strike hands with me in the conviction that the probabilities of the 

 future are at least so great as to render imperative the serious con- 

 sideration of our obligations toward it. 



It is a familiar geologic deduction that for long eras rains have 

 fallen on the lands and soils have grown in depth, while the surface 

 has been washed away. Soil-production and soil-removal have run 

 hand in hand, and yet they have been so controlled by the adjustments 

 of nature that no large part of the surface has been swept bare enough 

 to altogether exclude vegetation. More than this, it appears that the 

 usual adjustments of nature make rather for increasing fertility of soil 

 than depletion. It is true that at intervals deformations of the earth 

 have intervened giving mountainous heights and precipitous surfaces 

 from which the soil-product has been washed faster than it could be 

 produced; and desert conditions have also intervened locally; but these 

 diastrophic effects are perhaps rather rejuvenations necessary to the 

 preservation of the continents than destructive episodes. Whenever 

 such heights and slopes have been raised, the atmosphere and its waters 

 have at once begun to grade them down, to cover them with soil, and 

 to give to them a renewed habitability. So, in these and other ways, 

 the gifts of the great past now present themselves to us as the product 

 of a marvelous system of control which has checked excesses and 

 forced movement toward the golden means in which have lain pro- 

 ductivity and congeniality to life. Thus has come our inheritance of 

 a land suitable for habitation, of a soil-mantle of great fertility, of a 

 precipitation conducive to productiveness, and of a system of streams 

 endowed with great possibilities of water-foods, of power and of 

 navigation. 



We do not hesitate to enter into the inheritance, but what part 

 shall we take in the regulative system that produced and maintains it? 

 How shall we cooperate with nature in rendering conditions still more 

 serviceable to ourselves, and in transmitting a still greater inheritance 

 for our successors? Clearly we may use the proper revenues of our 

 inheritance, but surely we should not rob our successors of their share 

 in it. 



Let us turn at once to the basal factors in the problem, the rain- 

 fall, the soil-formation and soil-wastage, the special theme of this hour. 

 The rainfall may be regarded as an inherited asset, the soil is clearly 

 an inherited asset, even a little soil-removal is an advantage, but reck- 

 less soil-wastage is a serious error. Soils are the product of the 

 atmosphere and its waters modifying the rock surface. When they 

 have aided the air in producing soil by rock decay, the atmospheric 

 waters may pass either into plants or back to the surface through the 

 soil and out by evaporation, or they may pass on down to the ground- 

 waters and thence into the streams, furnishing there the basis for 



